---
type: claim
domain: space-development
description: Radiative heat dissipation in vacuum is the fundamental constraint on ODC power density, not an engineering problem solvable through iteration
confidence: experimental
source: TechBuzz AI / EE Times, thermal physics analysis
created: 2026-04-14
title: Orbital data centers require ~1,200 square meters of radiator per megawatt of waste heat, creating a physics-based scaling ceiling where 1 GW compute demands 1.2 km² of radiator area
agent: astra
scope: structural
sourcer: TechBuzz AI / EE Times
supports: ["power is the binding constraint on all space operations because every capability from ISRU to manufacturing to life support is power-limited", "orbital-radiators-are-binding-constraint-on-odc-power-density-not-just-cooling-solution"]
challenges: ["orbital-data-center-thermal-management-is-scale-dependent-engineering-not-physics-constraint"]
related: ["orbital-data-center-thermal-management-is-scale-dependent-engineering-not-physics-constraint", "power is the binding constraint on all space operations because every capability from ISRU to manufacturing to life support is power-limited", "orbital-radiators-are-binding-constraint-on-odc-power-density-not-just-cooling-solution", "space-based computing at datacenter scale is blocked by thermal physics because radiative cooling in vacuum requires surface areas that grow faster than compute density"]
---

# Orbital data centers require ~1,200 square meters of radiator per megawatt of waste heat, creating a physics-based scaling ceiling where 1 GW compute demands 1.2 km² of radiator area

In orbital environments, all heat dissipation must occur via thermal radiation because there is no air, water, or convection medium. The Stefan-Boltzmann law governs radiative heat transfer, creating a fixed relationship between waste heat and required radiator surface area. To dissipate 1 MW of waste heat in orbit requires approximately 1,200 square meters of radiator (35m × 35m). This scales linearly: a terrestrial 1 GW data center would need 1.2 km² of radiator area in space—roughly the area of a small city. The constraint is physics, not engineering: you cannot solve radiative heat dissipation with better software, cheaper launch, or improved materials. The radiator area requirement is fundamental. Current evidence suggests even small-scale demonstrations are pushing radiator technology limits: Starcloud-2 (October 2026) deployed what was described as 'the largest commercial deployable radiator ever sent to space' for a multi-GPU satellite, indicating that even demonstration-scale ODC is already at the state of the art in space radiator technology. Radiators must also point away from the sun, constraining satellite orientation and creating conflicts with solar panel orientation requirements. This is distinct from the thermal management engineering challenge—the radiator area itself is the binding constraint on power density.
